Bistable flow control valve

ABSTRACT

A water sprinkling system wherein the distribution of fluid is controlled by a plurality of bistable flow control valves, each valve toggling between first and second flow positions in response to interruptions in applied fluid pressure at the valve inlet.

United States Patent Gilson 1 1 Nov. 5, 1974 1 1 BISTABLE FLOW CONTROL VALVE 3707,9142 1/1973 Hogel 137 11) 1 1 Inventor: Paul @1150, 10012 Highcliff 3123153 111333 13111511..::::1.......:11i55115111 51 1;

Santa Ana, Calif. 92705 FOREIGN PATENTS OR APPLICATIONS 122] May 1973 1,235,456 6/1971 Great Britain 137/119 1211 Appl- 364,038 OTHER PUBLICATIONS Fluid Logic And Circuit; IBM Technical Disclosure 152] 11.8. C1 137/119, 137/625, 235/201 ME, Bulletin; .1. H. Meier; V01. 6, No. 3, August 1963; pp.

[51] Int. Cl. F16k 11/00 158] Field of Search 137/119, 814, 829, 624.14; 235/201 ME; 239/66; 251/6l.1, 75

References Cited UNITED STATES PATENTS Primary Examiner-Robert G. Nilson Attorney. Agent, or Firm-Knobbe, Martens, Olson, Hubbard & Bear [57] ABSTRACT A water sprinkling system wherein the distribution of fluid is controlled by a plurality of bistable flow control valves, each valve toggling between first and second flow positions in response to interruptions in applied fluid pressure at the valve inlet.

7 Claims, 11 Drawing Figures 1 I nu/a f7 pears?! PATENIEDNUV 5mm v 3345;???

' slur an? 4 BISTABLE FLOW CONTROL VALVE BACKGROUND OF THE INVENTION This invention pertains to water sprinkling systems comprising a plurality of sprinkler nozzles wherein the pressure applied to the water sprinkling system effects a change of state in a plurality of flow control valves connected to groups of sprinkler nozzles to permit sequencing of the fluid flow to different groups of sprinkler nozzles. More particularly this invention relates to a flow control system wherein the pressure of the main fluid flow is utilized to control the sequencing of a plurality of remote passive valves in order to divert the fluid flow to different fluid dispensing stations.

The most common sprinkler control systems today include a plurality of hydraulically or electrically controlled valves stationed in a fluid distribution system wherein each of the valves is independently operable by a hydraulic or electric signal conducted to the various valves through independent wires or hydraulic conduits. The wires or conduits in such a system are then connected to a main sprinkler control system which typically utilizes a clock mechanism to sequence the various sprinkler control valves by producing output signals on the lines or conduits. Typically these output signals have a duration at a particular valve which is equal to the desired duration of water application at a set of sprinklers. Such systems are subject to numerous shortcomings, not the least of which is excessive cost. Thus, each of these remote flow control valves is necessarily a relatively complex mechanical device in order to permit the control of a high pressure fluid through the operation of an electrical solenoid or a hydraulic actuator. These devices are subject to wear and to malfunction due to impurities in the fluid being controlled so that they must be replaced periodically. Additionally, it is not uncommon in a system of the prior art type for the cost of the plurality of flow control valves to exceed the costs of the flow control timing station, such that the overall cost becomes quite expensive as the number of flow control valves increases.

A further detrimental feature of the prior art systems is caused by the necessity of connecting flow control circuits, either hydraulic or electric, to each of the remote valves from the central control station. These circuits are typically buried and, in the electrical form of the valve, present shock hazards which are common to any type of buried electrical cabling system. In addition, fault diagnosis in the prior art systems is extremely difficult, since it is possible to have a fault anywhere along the hydraulic or electrical circuit leading from the remote valve to the central control station and it is often necessary to unearth a long section of the control circuit when a fault occurs in order to locate the position of the fault.

Furthermore, the application of prior art automatic sprinkler control systems to existing manual control sprinkler installations often involves the installation of hydraulic or electrical circuits in previously landscaped areas, requiring partial destruction of the landscape in order to bury the circuit elements.

SUMMARY OF THE INVENTION The present invention alleviates many of the difficulties of the prior art sprinkler control systems including those which are enumerated above. The sprinkler control system of the present invention includes remote flow control valves which are responsive to the main flow from the fluid source rather than being responsive to an auxiliary, hydraulic or electrical circuit. Thus, the remote valve of the present system may be installed directly into the flow control lines without the requirement for any additional hydraulic or electrical circuitry, thereby avoiding the necessity of burying additional circuits and the difficulty of determining what part of a buried circuit is faulty.

The present invention requires only a single hydraulically or electrically actuated master flow control valve which may be conveniently situated adjacent the flow control timing system to avoid the necessity for lengthy buried circuits. A plurality of slave flow control valves may then be connected in the fluid distribution system,.

each valve being responsive to the actuation of the master flow control valve. Since each of the slave flow control valves may be made at a relatively low cost,.the entire cost of the flow control systems, particularly where a large number of independent flow circuits are to be controlled, is substantially reduced.

Each of the slave flow control valves of the present invention operates as a bistable device which changes from a first stable state to a second stable state in response to pressure variation in the main flow control line. Each of these slave valves is self-complimenting; that is, the valves likewise change from the second stable state to the first stable state in response to a comparable pressure change in the flow control system, so that the valves may be arranged in a binary pattern to control as many sprinkler circuits as may be desired.

Each of the slave control valves of the present invention includes an inlet port and a pair of outlet ports. A vane is positioned between the inlet and outlet ports in order to sequence the application of fluid at the inlet port alternately to the outlet ports. This vane is responsive to the application of pressure at the inlet port and the interruption of pressure after such application for changing the state of the vane from one stable position to an alternate stable position so that each reapplication of pressure, regardless of the time duration of the pressure interruption, will position the valve to connect an alternate one of the outlet ports to the inlet port. In order to utilize such a slave fluid control valve in a sprinkler system, a first slave valve is installed with its inlet port connected to the main flow line and its outlet ports connected to the inlet ports of a pair of additional slave control valves. In this fashion, each of the slave control valves may then be connected to either a pair of slave control valves or to a pair of water sprinkling circuits so that the entire system will sequence through each of the sprinkling circuits in a binary fashion. Each sprinkler circuit may then be operated for the desired period of time, and the fluid source interrupted to sequence the system to the next sprinkler circuit.

The flow control vane of the slave fluid control valves of the present invention are preferably a one piece flexible resilient reed which may be constructed from thin metal shim stock, for example, which is under axial compression due to its confined axial mounting within a valve housing. The axial compression on this reed member causes the reed member to bow to relieve the axial stress, such that it is stable when bowed in either of two directions. The walls of the valve housing are constructed such that, when fluid pressure is applied to the valve, the vane will be contorted into a position which seals one of the outlet valve ports while at the same time cocking the vane so that, when pressure is removed, the vane will relax to its second bowed position in preparation for closing of the alternate outlet valve port on the reapplication of pressure to the inlet ort.

p These and other features of the present invention may best be understood by reference to the drawings in which:

FIG. 1 is a schematic diagram of a sprinkler system itilizing the bistable flow control valve of the present invention;

FIG. 2 is a chart showing the sequencing pattern of 1 the sprinkler system of FIG. 1;

FIG. 3 is an exploded perspective view of the bistable flow control valve used in the sprinkler system of FIG.

FIG. 4 is a sectional view of the flow control valve of FIG. 3 taken at line 4-4 of FIG. 3;

FIGS. 5 through are sectional views taken through line 5-5 of FIG. 4, showing the bistable flow control valve of the present invention in a plurality of flow control positions; and

FIG. 11 is a sectional view similar to that of FIG. 4, but showing an alternate embodiment of the reed structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1, the bistable flow control valve of the present invention is designed primarily for use in a flow control system such as the water sprinkler system shown in FIG. 1. In an exemplary system of this type, a fluid pressure source 10 supplies water under pressure through a line 12 to a solenoid valve 14 which is capable of interrupting the flow in the line 12 to produce an interruptable flow at a line 16. It will be readily understood that the fluid source 10 may be, for example, the local water main which supplies water under pressure to a municipality or may be a reservoir of some sort provided with a pump for supplying water under pressure. In the instance where the fluid pressure source 10 is a reservoir and a pump in combination, the solenoid valve 14 may be eliminated from the system since the water pressure in the line 16 may be controlled by simply energizing and de-energizing the The solenoid valve 14 is controlled through either a hydraulic or electrical control line 18 which is connected to a valve timer control 20. The valve timer control 20 is similar to the sprinkler timing controls which are readily available, except that it is required to energize and to de-energize only a single solenoid valve 14. During operation the valve timer control 20 will sequence the solenoid valve 14 to repetitively interrupt the flow of fluid under pressure from line 12 and, between such interruptions, to open the solenoid valve 14 for extended time periods to allow the application of fluid through the sprinkler system.

The fluid line 16 is connected to a binary series of fluid control slave valves 22, 24, 26, 28, 30, 32 and 34. By binary array is meant that each of the slave valves 22 through 34 controls two additional valves or output devices in sequence. Thus, for example, the flow in the line 16 is applied to the slave valve 22 to connect the fluid pressure source to either of the outlets 22a or 22b in response to application of pressurized fluid at the inlet 22c. Note that each of the valves in FIG. 1 includes an inlet, labeled 0 and two outlets labeled a and 12. These designations will be combined, hereinafter, with the valve number, such as 22a, to designate the a outlet of valve 22. The outlets 22a and 22b are, in turn, connected respectively in the inlets 24c and 260 of an additional pair of slave fluid control valves. In a similar fashion valves 24 and 26 are connected respectively to valves 28 and 30, on the one hand, and valves 32 and 34 on the other hand. Each of the final valves in the binary sequence, namely valves 28, 30, 32 and 34, has its outlets a and I: connected respectively to a pair of fluid dispensing stations which, in the preferred embodiment, are sprinkler nozzles 36, 38, 40, 42, 44, 46, 48 and 50. It will be readily recognized by those familiar with the water sprinkling art that any one of the sprinklers 36 through may represent a series of sprinklers each of which are designed to apply water simultaneously to cover an enlarged area. It is the primary function of the slave fluid control valves 22 through 34 to operate in such a manner as to apply water sequentially to the fluid dispensing station 36 to 50. Such sequential application is typical since the fluid pressure source 10 is usually not capable of supplying the required pressure level to the dispensing stations 36 through 50 to'operate them all simultaneously. Also, it is often desirable to vary the length of time that the sprinklers are turned on.

Each of the slave fluid control valves 22 through 34 is designed to operate in response to operation of the solenoid valve 14 without any additional electrical or hydraulic connections between the slave valves 22 through 34 and the valve timer control 20. Each of the slave fluid control valves 22 through 34 changes state in response to the application of fluid pressure to the valve and the interruption of such pressure. Thus, for example, if the slave control valve 22 is in a first relaxed position, application of pressure on the line 16 will supply pressure to the inlet 22c of the valve 22 and the valve 22 will operate in response to this pressure application to close the outlet 22b and to open the outlet 22a to connect water between the line 16 and the inlet 24c of the slave fluid control valve 24. When this water pressure is interrupted, the slave control valve 22 will change state to a second relaxed position so that a reapplication of water pressure in the line 16 will close the outlet 22a and open the outlet 22b to connect the line 16 to the inlet port 260 of the slave fluid control valve 26. Each of the slave fluid control valves therefore operates as a bistable device, connecting the flow of water at its inlet 22c through 34c to one or the other of its outlets 22a/b through 34a/b in response to the application and interruption of water pressure at its inlet 22c through 340.

The overall operation of the sprinkler control system of FIG. 1 is best understood by reference to FIG. 2 which is a chart showing the operation of the various slave control valves 22 through 34 in response to successive operation of the solenoid valve 14 to interrupt the water pressure in the line 16. The initial relaxed position of each valve is shown following the initial position 1 in FIG. 2, indicating that each of the valves is in position a. If the solenoid valve 14 is now opened, the valve 22 will channel water to its outlet 22a so that the line 16 is connected to the slave control valve 24. Since valve 24 is in the a position, it will channel water from its outlet 24a to the valve 28 which will, in turn, channel water to its outlet 28a and hence to the dispensing station 36 as shown in line 1 of FIG. 2. It should be noted that the water pressure has been applied only to valves 22, 24 and 28 and, therefore, when the solenoid valve 14 closes, regardless of the duration of its closure, only the valves 22, 24 and 28 will change state to their alternate stable position as shown in position 2 of FIG. 2. Thus valves 22, 24 and 28 are now in the b position, indicating that the next application of water pressure will connect their inlet c to their outlet b. Each of the remaining valves has remained in the a position as shown in line 2 of FIG. 2. A reapplication of water pressure to the system caused by an opening of the solenoid valve 14 will now conduct water through the outlet 22b of the slave control valve 22 to the valve 26. Since the valve 26 is still in its a position, it will conduct the flow of water to the valve 32 which, being also in its a position, will conduct the flow of water to the dispensing station 44. In this manner each of the valves to which water pressure has been previously applied will sequence on the interruption of applied water pressure so that the next time water is supplied to this valve it will apply the inlet water flow to an alternate one of its pair of outlets. It can be seen, therefore, from FIG. 2 that the valves will sequence through a total of eight positions, dispensing water in turn to each of the fluid dispensing stations 36 through 50 in the sequence shown in FIG. 2, and will then return to its initial position as shown at line 9 in FIG. 2, again applying fluid to dispensing station 36. It can be seen that, through the operation of only one valve, that is, the solenoid valve 14, the valve timer control can repetitively interrupt the flow of fluid to the fluid control system and thereby sequentially operate a plurality of valves. The time duration between such interruptions will determine the duration of water application at each dispensing station so that the duration at each station may be independently controlled. By introducing additional valves in place of the dispensing stations 36 to 50, a substantially limitless number of dispensing stations can be serviced by such a system, without the introduction of additional solenoid valves.

The use of the slave control valves 22 through 34 can greatly reduce the cost of the overall flow control system only if the slave control valve can be made substantially cheaper than solenoid control valves. The bistable flow control valve which is shown in FIGS. 3 through accomplishes this desirable result. Each of the slave control valves 22 to 34 of FIG. 1 are identical and the operation will therefore be explained in reference to slave control valve 22 in FIGS. 3 through 10.

Referring initially to FIGS. 3 and 4, the slave control valve 22 includes a valve body 52 which comprises a main valve housing 54 and a cover plate 56 which encloses the valve housing 54 in a watertight fashion. A plurality of bores such as the bores 58 and 60 may be formed in the housing 54 and the cover 56 to accommodate bolts for securing the cover 56 over the housing 54 in a watertight fashion. Alternatively, the cover 56 may be attached to the housing 54 in any manner which will produce a watertight body 52. Within the housing 54 is a flexible reed 62 which is maintained within the housing 54 in a pair of axially aligned grooves 64 and 66. If the reed 62 were removed from the housing 64, it would lie in a plane and have a given length. The distance between the apacies of the grooves 64 and 66 of the housing 54, however, is shorter than this relaxed length of the reed 62 so that, when the reed 62 is placed within the housing 64, it will assume a bowed configu-' ration as shown in FIG. 3. The housing 54 additionally includes a pair of stops or abutments 68 and 70 which, in the preferred embodiment, are molded as a portion of the sidewall of the housing 54. These stops are positioned opposite one another and in close enough proximity to force the reed 62 to assume a second order bowed configuration when it is placed within the housing 54. That is, it is impossible for the reed 62 to simply bend in one direction in order to accommodate its excessive length between the apacies of the grooves 64 and 66, and it is therefore forced into a double-bowed configuration as shown in FIG. 3.

The housing 54 additionally includes an inlet 22c in the vicinity of the groove 64 and a pair of outlets 22a and 22b in the vicinity of the groove 66. The inlet 22c is conveniently positioned to surround the groove 64 so that water may be applied to an inlet cavity 72 of the housing 54 regardless of the position of the reed 62. The outlets 22a and 22b are each conveniently connected to a port which terminates in a concave surface 74 and 76 which is formed between the abutments 68 and 70, respectively, and the groove 66. These concave surfaces 74 and 76 are designed to accommodate the surface of the reed 62 during the operation of the valve in such a manner that the reed 62 may close, alternatively, the outlets 22a and 22b. The reed 62 is advantageously cut away on each side, as shown at 78 and 80, to provide a free flow of fluid around the inlet extremity of the reed 62 in the inlet cavity 72 during operation of the valve. These cut-away portions 78 and 80 are shown even more clearly in FIG. 4. In addition to permitting the free flow in the inlet cavity 72, the cut-away portions 78 and 80 of the reed 62 produce an area in the reed 62 between the abutments 68 and 70 and the groove 64 which has less-torsional strength than the area. of the reed between the abutments 68 and 70 and the groove 66. Thus the portion of the reed which is adjacent the inlet 22c has less resistance to bowing than does that portion of the reed 62 in the vicinity of the outlets 22a and 22b, so that displacement of the reed in the vicinity of the outlets 22a and 22b, as will be discussed below, will more readily cause a resulting displacement in the portion of the reed 62 which is adjacent to the inlet 22c.

Referring now to FIGS. 6 through 10, the operation of the slave flow control valve 22 of FIGS. 3 and 4 may be described. Referring initially to FIG. 5, the reed 62 is shown in its initial relaxed position comparable to the position shown in FIG. 3, with the reed 62 axially biased between the grooves 64 and 66 and abutting the abutment 68 to cause the reed 62 to attain an initial relaxed second order bowed configuration. If fluid is applied to the inlet 220, the reed 62 will allow free flow of the fluid in the inlet cavity 72, but the engagement of the reed 62 against the abutment 68 will prohibit flow of fluid in the vicinity of the outlet 22a. Thus, the reed, being in contact with the abutment 68 throughout the width of both the reed 62 and the abutment 68 will permit flow between the abutments 68 and 70 only on the side of the reed 62 which is adjacent the outlet 22b. As pressure within the valve 22 increases due to restrictions beyond the outlet 2211, a net force, as shown by the arrow 82 will be applied to the portion of the reed 62 between the abutment 68 and the groove 66, there being no substantial water pressure in the outlet 22a. This force shown by the arrow 82 will continue to increase as pressure within the valve housing 72 increases, causing a displacement of the reed 62 to the configuration shown in FIG. 6, creating a third order bend in the reed 62 as it bends over the abutment 68. The tensile strength in the reed 62 will oppose this displacement, since more energy is absorbed by the reed 62 in a third order bend than was absorbed in the second order bend of FIG. 5. Once the reed has been displaced to approximately the position shown in FIG. 6, the bending moment in the reed around the abutment 68 will cause the reed 62 in the vicinity of the inlet cavity 72 to relieve this additional bending stress by snapping to the configuration shown in FIG. 7, that is, to another second order bending configuration, allowing the force shown by the arrow 82 to close the outlet 22b by seating the reed 62 firmly against the surface 76. The configuration of the reed 62 shown in FIG. 7 will remain so long as water pressure is applied at the inlet 22c and the slave control valve 22 will continue to channel water between the inlet 22c and the outlet 22b which has been opened to its maximum extent by the displacement of the reed 62 to the position shown in FIG. 7. If the application of pressure to the inlet 220 is now interrupted, as by the solenoid valve 14 of FIG. 1, the reed 62 will achieve its alternate relaxed position as shown in FIG. 8, relieving as much stress within the reed 62 as possible by bowing to a position in which the reed 62 is in contact with the abutment 70. It will be recognized, through an observation of FIGS. and 8, that the reed can achieve two alternate relaxed positions as shown in these figures, one of which creates a contact between the reed 62 and the abutment 68 and the other of which creates a contact between the reed 62 and the abutment 70.

If water pressure is reapplied to the slave control valve 22 in its configuration shown in FIG. 8, water will freely flow in the inlet channel 72 and pressure will again build up within the valve to generate a second, opposite force as shown by the arrow 84. Since the area of the valve housing 54 in the vicinity of the outlet 2212 has been closed by the contact of the reed 62 with the abutment 70, as pressure builds up within the valve housing 54 the force shown by the arrow 84 will displace the reed to the configurations shown in FIGS. 9 and 10 until the outlet 22!? is abutted by the reed 62, closing the outlet 22b and connecting the inlet 220 for flow to the outlet 22a. When the pressure at the inlet 22c is again interrupted, the reed will again achieve its first relaxed position as shown in FIG. 5, so that an additional reapplication of pressure to the inlet 22c will again close off the outlet 22a and open the outlet 2212. It can be readily seen, therefore, that the slave fluid control valve 22 shown in FIGS. 3 through 10 operates as a self-complimenting bistable fluid control valve, that is, it will alternatively connect the inlet 220 to the outlets 22a and 22b in response to each application and interruption of fluid pressure at the inlet 22c regardless of the duration of the interruption of fluid pressure. The slave control valve 22 will remain in a position connecting the inlet 22c to one of the outlets 220 or 22b so long as pressure is applied to the valve 22. However, each interruption of the applied pressure, regardless of the length of the interruption, will cause the reed 62 to-achieve its alternate relaxed position as shown in FIGS. 5 and 8, preparing the valve 22 for connection to an alternate outlet.

It should be noted that any planar configuration of the reed 62, as viewed in FIG. 4, is possible, so long as some fluid is allowed to flow past the reed 62 in the inlet cavity 72. Thus, it is possible to form a rectangular reed with a variety of apertures in the reed in the area included in the inlet cavity 72, or with a totally rectangular reed 62 having a width which is sufficiently less and the width of the housing 54 to permit flow of fluid in the inlet cavity 72 around the outside of the reed 62.

In addition, as shown in FIG. 4, it has been found advantageous to cut away the edges of the reed 62 as shown at 88 to form a pair of bearing edges 85. This assures that the sides of the reed 62 will not bind within the housing 54 as the reed moves.

It has been noted that the valve shown in FIG. 3 is subject to occasional failure if sand or gravel is applied with the water to the inlet 220, since such impurities can lodge between the edges 88 of the reed 62 and the cover 66 or the bottom wall of the housing 54. It has been discovered that this lodging occurs primarily due to water flow around the edges 88 as the reed 62 is moved to close the outlets 22a and 22b. That is, a small portion of the water flow will flow into the outlet 22a or 22b which is being closed (as shown in FIGS. 6 and 9) prior to the final closing of the particular outlet, and will carry with it grains of sand which may lodge between the reed 62 and the housing 54. In order to prohibit such interference by impurities, an alternate embodiment of the reed 62 may be constructed as shown in FIG. 11. Additional apertures 86 are formed in the reed 62 to permit the small amount of water flow passing to the outlet 22a or 22b during closure to flow through the apertures 86. The impurities which may flow in the water are therefore not forced into the small openings 88 and the valve of FIG. 11 is relatively unsusceptible to malfunction due to impurities in the water.

It should be noted, in reference to FIG. 3, that the inlet 220 may be connected to the water inlet chamber 72 in any position, and may, for example, enter the housing 54 parallel to one of the outlet ports 22a and 22b rather than in the vicinity of the groove 64, without interferring with the operation of the valve.

It is further noteworthy that the reed 62 need not be constructed in a one piece fashion of the preferred embodiment shown and described herein but rather may be constructed in any manner which will produce an axial stress within the reed 62. Thus, for example, the valve has been satisfactorily operated using a coil spring to induce axial stress in a shortened reed to induce a first order bowing of the reed when the valve is closed in either direction, a straight reed when the valve is in either of its relaxed positions, and a second order bowing configuration when the valve is being adjusted between its straight configuration and its closed configuration.

An exemplary model of the preferred embodiment shown in FIGS. 2 through 10 has been constructed and found to operate satisfactorily through 292, 406 cycles. In this model, the valve body 52 was constructed of casting resin, the length of the cavity between the apex of the groove 64 and the apex of the groove 66 being 3.627 inches, the width of the cavity 72, as viewed in FIGS. 4, being 1.723 inches, and the distance between the abutments 68 and 70 being 0.350 inches. In this model, the reed 62 was constructed of 302 full hard stainless steel sheet, 0.005 inches thick, 1.713 inches wide, 3.743 inches long, relieved along the edges 88 (F IG. 4) by 0.020 inches and having a width between edges 78 and 80 (FIG. 4) of 0.595 inches. This model required approximately 3 psi minimum pressure for operation.

What is claimed is:

1. A bistable fluid valve, comprising:

a housing having an inlet and first and second outlets;

a flexible reed mounted within said housing and biased axially to bow within said housing in either of first and second directions;

means responsive to fluid pressure at said inlet for changing the direction of bow of said reed; and

means responsive to said reed for closing said first or second outlet in response to said reed being bowed in said first or second direction, respectively.

2. A bistable fluid valve as defined in claim 1 additionally comprising:

a pair of abutments positioned in said housing to interfere with the normal bow of said flexible reed to force said flexible reed to undergo higher order bending configurations.

3. A bistable fluid valve as defined in claim 2 wherein said pair of abutments forces said reed to vary between second and third order bending configurations.

4. A bistable fluid valve, comprising:

a valve housing having an inlet and first and second outlets;

a valve member movable within said valve housing between a pair of stable positions for blocking said first and second outlets, respectively, said valve member being a flexible reed;

means for storing energy in said valve member when pressure is applied to said valve inlet, said means for storing energy comprising means for flexing said flexible reed; and

means for changing the stable position of said valve member in response to interruption of pressure at said inlet, said means utilizing said stored energy to effect said change.

5. A bistable fluid valve as defined in claim 4 wherein said means for storing energy flexes said reed to higher order bending configuration from the normal relaxed configuration of said reed.

6. A fluid valve, comprising:

a valve body;

an inlet in said valve body;

first and second outlets in said valve body;

a valve member mounted in said valve body to move between two stable positions, said stable positions interposing said valve member between said inlet and said first or second outlet, respectively; and

means for changing the position of said valve member from one of said stable positions to the other in response to interruption of fluid pressure at said valve inlet, said means for changing the position of said valve member comprising;

a pair of impediments mounted in said valve body within the path of said valve member;

clearance within said valve housing between each of said stable positions and a sealed position sealing each of said first and second outlets; and

means for flexing said valve member to bend said valve member around said impediments to permit said valve member to seal one of said first and second outlets and to thereby cock said valve member for relaxation to the other of said stable positions.

7 A valve, comprising:

a valve housing having an inlet chamber, an inlet in said inlet chamber, and first and second outlets outside of said inlet chamber;

a valve member extending within said housing into said inlet chamber, said valve member being a unitary flexible reed;

means for storing energy in said valve member within said inlet chamber in response to the application of fluid pressure to said inlet; and

means responsive to said valve member for alternatively closing said first and second outlets, said means utilizing said energy stored in said valve member to effect said closing. 

1. A bistable fluid valve, comprising: a housing having an inlet and first and second outlets; a flexible reed mounted within said housing and biased axially to bow within said housing in either of first and second directions; means responsive to fluid pressure at said inlet for changing the direction of bow of said reed; and means responsive to said reed for closing said first or second outlet in response to said reed being bowed in said first or second direction, respectively.
 2. A bistable fluid valve as defined in claim 1 additionally comprising: a pair of abutments positioned in said housing to interfere with the normal bow of said flexible reed to force said flexible reed to undergo higher order bending configurations.
 3. A bistable fluid valve as defined in claim 2 wherein said pair of abutments forces said reed to vary between second and third order bending configurations.
 4. A bistable fluid valve, comprising: a valve housing having an inlet and first and second outlets; a valve member movable within said valve housing between a pair of stable positions for blocking said first and second outlets, respectively, said valve member being a flexible reed; means for storing energy in said valve member when pressure is applied to said valve inlet, said means for storing energy comprising means for flexing said flexible reed; and means for changing the stable position of said valve member in response to interruption of pressure at said inlet, said means utilizing said stored energy to effect said change.
 5. A bistable fluid valve as defined in claim 4 wherein said means for storing energy flexes said reed to higher order bending configuration from the normal relaxed configuration of said reed.
 6. A fluid valve, comprising: a valve body; an inlet in said valve body; first and second outlets in said valve body; a valve member mounted in said valve body to move between two stable positions, said stable positions interposing said valve member between said inlet and said first or second outlet, respectively; and means for changing the position of said valve member from one of said stable positions to the other in response to interruption of fluid pressure at said valve inlet, said means for changing the position of said valve member comprising: a pair of impediments mounted in said valve body within the path of said valve member; clearance within said valve housing between each of said stable positions and a sealed position sealing each of said first and second outlets; and means for flexing said valve member to bend said valve member around said impediments to permit said valve member to seal one of said first and second outlets and to thereby cock said valve member for relaxation to the other of said stable positions.
 7. A valve, comprising: a valve housing having an inlet chamber, an inlet in said inlet chamber, and first and second outlets outside of said inlet chamber; a valve member extending within said housing into said inlet chamber, said valve member being a unitary flexible reed; means for storing energy in said valve member within said inlet chamber in response to the application of fluid pressure to said inlet; and means responsive to said valve member for alternatively closing said first and second outlets, said means utilizing said energy stored in said valve member to effect said closing. 